Patent Literature 1 discloses an oil mist filter (33) and an oil separator (31) using the oil mist filter (33) (see FIG. 6). This oil mist filter (33) includes a ring-shaped support body (48) and a circular plate-shaped filter body (47). The filter body (47) is stuck on one surface of the support body (48). The filter body (47) closes a hole (49) at a center of the support body (48). A housing (32) of the oil separator (31) internally houses the support body (48) and the filter body (47). The support body (48) and the filter body (47) partition an internal space of the housing (32) into an inflow port side and an outflow port side. When blow-by gas passes through the filter body (47), the filter body (47) captures an oil mist.